Have you tried the "Testing Authentication" utility? Also, what model and version of ZoneDirector are you running? Did you try to remove the "RADIUS" WLAN as suggested?
Here is how you can try the "Testing Authentication" utility.
1. On the Configure > AAA Servers page, locate the Test Authentication Settings section.
2. Select the authentication server that you want to use from the Test Against drop-down
menu.
3. In User Name and Password, enter an Active Directory, LDAP or RADIUS user name and
password.
4. Click Test.
If ZoneDirector was able to connect to the authentication server and retrieve the configured
groups/attributes, the information appears at the bottom of the page. The following is an
example of the message that will appear when ZoneDirector:
* authenticates successfully with
the server:
Success! Groups associated with this user are “{group_name}”. This
user will be assigned a role of {role}.
If the test was unsuccessful, there are three possible results (other than success) that will be
displayed to inform you if you have entered information incorrectly:
• Admin invalid
• User name or password invalid
• Search filter syntax invalid (LDAP only)
Based on the message you provided, it seems to be a problem between zonedirector and radius server. What Radius server are you using? Can you look at the logs of the Radius server and see what is telling you. A couple of things I can think are. "Shared secret" not matching. The incorrect IP address defined in the Radius configuration (on the radius server side). Invalid userna/password. To know all of this, we would need to know what radius server you are using.